[linux.git] / fs / nfs / nfs4super.c

/*
 * Copyright (c) 2012 Bryan Schumaker <[email protected]>
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/nfs_idmap.h>
#include <linux/nfs4_mount.h>
#include <linux/nfs_fs.h>
#include "delegation.h"
#include "internal.h"
#include "nfs4_fs.h"
#include "dns_resolve.h"
#include "pnfs.h"
#include "nfs.h"

#define NFSDBG_FACILITY		NFSDBG_VFS

static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
static void nfs4_evict_inode(struct inode *inode);
static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *raw_data);
static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *raw_data);
static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *raw_data);

static struct file_system_type nfs4_remote_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs4_remote_mount,
	.kill_sb	= nfs_kill_super,
	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};

static struct file_system_type nfs4_remote_referral_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs4_remote_referral_mount,
	.kill_sb	= nfs_kill_super,
	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};

struct file_system_type nfs4_referral_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs4_referral_mount,
	.kill_sb	= nfs_kill_super,
	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};

static const struct super_operations nfs4_sops = {
	.alloc_inode	= nfs_alloc_inode,
	.destroy_inode	= nfs_destroy_inode,
	.write_inode	= nfs4_write_inode,
	.drop_inode	= nfs_drop_inode,
	.put_super	= nfs_put_super,
	.statfs		= nfs_statfs,
	.evict_inode	= nfs4_evict_inode,
	.umount_begin	= nfs_umount_begin,
	.show_options	= nfs_show_options,
	.show_devname	= nfs_show_devname,
	.show_path	= nfs_show_path,
	.show_stats	= nfs_show_stats,
	.remount_fs	= nfs_remount,
};

struct nfs_subversion nfs_v4 = {
	.owner = THIS_MODULE,
	.nfs_fs   = &nfs4_fs_type,
	.rpc_vers = &nfs_version4,
	.rpc_ops  = &nfs_v4_clientops,
	.sops     = &nfs4_sops,
	.xattr    = nfs4_xattr_handlers,
};

static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
{
	int ret = nfs_write_inode(inode, wbc);

	if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
		int status;
		bool sync = true;

		if (wbc->sync_mode == WB_SYNC_NONE)
			sync = false;

		status = pnfs_layoutcommit_inode(inode, sync);
		if (status < 0)
			return status;
	}
	return ret;
}

/*
 * Clean out any remaining NFSv4 state that might be left over due
 * to open() calls that passed nfs_atomic_lookup, but failed to call
 * nfs_open().
 */
static void nfs4_evict_inode(struct inode *inode)
{
	truncate_inode_pages(&inode->i_data, 0);
	clear_inode(inode);
	pnfs_return_layout(inode);
	pnfs_destroy_layout(NFS_I(inode));
	/* If we are holding a delegation, return it! */
	nfs_inode_return_delegation_noreclaim(inode);
	/* First call standard NFS clear_inode() code */
	nfs_clear_inode(inode);
}

/*
 * Get the superblock for the NFS4 root partition
 */
static struct dentry *
nfs4_remote_mount(struct file_system_type *fs_type, int flags,
		  const char *dev_name, void *info)
{
	struct nfs_mount_info *mount_info = info;
	struct nfs_server *server;
	struct dentry *mntroot = ERR_PTR(-ENOMEM);

	mount_info->set_security = nfs_set_sb_security;

	/* Get a volume representation */
	server = nfs4_create_server(mount_info, &nfs_v4);
	if (IS_ERR(server)) {
		mntroot = ERR_CAST(server);
		goto out;
	}

	mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);

out:
	return mntroot;
}

static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
		int flags, void *data, const char *hostname)
{
	struct vfsmount *root_mnt;
	char *root_devname;
	size_t len;

	len = strlen(hostname) + 5;
	root_devname = kmalloc(len, GFP_KERNEL);
	if (root_devname == NULL)
		return ERR_PTR(-ENOMEM);
	/* Does hostname needs to be enclosed in brackets? */
	if (strchr(hostname, ':'))
		snprintf(root_devname, len, "[%s]:/", hostname);
	else
		snprintf(root_devname, len, "%s:/", hostname);
	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
	kfree(root_devname);
	return root_mnt;
}

struct nfs_referral_count {
	struct list_head list;
	const struct task_struct *task;
	unsigned int referral_count;
};

static LIST_HEAD(nfs_referral_count_list);
static DEFINE_SPINLOCK(nfs_referral_count_list_lock);

static struct nfs_referral_count *nfs_find_referral_count(void)
{
	struct nfs_referral_count *p;

	list_for_each_entry(p, &nfs_referral_count_list, list) {
		if (p->task == current)
			return p;
	}
	return NULL;
}

#define NFS_MAX_NESTED_REFERRALS 2

static int nfs_referral_loop_protect(void)
{
	struct nfs_referral_count *p, *new;
	int ret = -ENOMEM;

	new = kmalloc(sizeof(*new), GFP_KERNEL);
	if (!new)
		goto out;
	new->task = current;
	new->referral_count = 1;

	ret = 0;
	spin_lock(&nfs_referral_count_list_lock);
	p = nfs_find_referral_count();
	if (p != NULL) {
		if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
			ret = -ELOOP;
		else
			p->referral_count++;
	} else {
		list_add(&new->list, &nfs_referral_count_list);
		new = NULL;
	}
	spin_unlock(&nfs_referral_count_list_lock);
	kfree(new);
out:
	return ret;
}

static void nfs_referral_loop_unprotect(void)
{
	struct nfs_referral_count *p;

	spin_lock(&nfs_referral_count_list_lock);
	p = nfs_find_referral_count();
	p->referral_count--;
	if (p->referral_count == 0)
		list_del(&p->list);
	else
		p = NULL;
	spin_unlock(&nfs_referral_count_list_lock);
	kfree(p);
}

static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
		const char *export_path)
{
	struct dentry *dentry;
	int err;

	if (IS_ERR(root_mnt))
		return ERR_CAST(root_mnt);

	err = nfs_referral_loop_protect();
	if (err) {
		mntput(root_mnt);
		return ERR_PTR(err);
	}

	dentry = mount_subtree(root_mnt, export_path);
	nfs_referral_loop_unprotect();

	return dentry;
}

struct dentry *nfs4_try_mount(int flags, const char *dev_name,
			      struct nfs_mount_info *mount_info,
			      struct nfs_subversion *nfs_mod)
{
	char *export_path;
	struct vfsmount *root_mnt;
	struct dentry *res;
	struct nfs_parsed_mount_data *data = mount_info->parsed;

	dfprintk(MOUNT, "--> nfs4_try_mount()\n");

	export_path = data->nfs_server.export_path;
	data->nfs_server.export_path = "/";
	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
			data->nfs_server.hostname);
	data->nfs_server.export_path = export_path;

	res = nfs_follow_remote_path(root_mnt, export_path);

	dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n",
		 PTR_ERR_OR_ZERO(res),
		 IS_ERR(res) ? " [error]" : "");
	return res;
}

static struct dentry *
nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
			   const char *dev_name, void *raw_data)
{
	struct nfs_mount_info mount_info = {
		.fill_super = nfs_fill_super,
		.set_security = nfs_clone_sb_security,
		.cloned = raw_data,
	};
	struct nfs_server *server;
	struct dentry *mntroot = ERR_PTR(-ENOMEM);

	dprintk("--> nfs4_referral_get_sb()\n");

	mount_info.mntfh = nfs_alloc_fhandle();
	if (mount_info.cloned == NULL || mount_info.mntfh == NULL)
		goto out;

	/* create a new volume representation */
	server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
	if (IS_ERR(server)) {
		mntroot = ERR_CAST(server);
		goto out;
	}

	mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
out:
	nfs_free_fhandle(mount_info.mntfh);
	return mntroot;
}

/*
 * Create an NFS4 server record on referral traversal
 */
static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
		int flags, const char *dev_name, void *raw_data)
{
	struct nfs_clone_mount *data = raw_data;
	char *export_path;
	struct vfsmount *root_mnt;
	struct dentry *res;

	dprintk("--> nfs4_referral_mount()\n");

	export_path = data->mnt_path;
	data->mnt_path = "/";

	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
			flags, data, data->hostname);
	data->mnt_path = export_path;

	res = nfs_follow_remote_path(root_mnt, export_path);
	dprintk("<-- nfs4_referral_mount() = %d%s\n",
		PTR_ERR_OR_ZERO(res),
		IS_ERR(res) ? " [error]" : "");
	return res;
}


static int __init init_nfs_v4(void)
{
	int err;

	err = nfs_dns_resolver_init();
	if (err)
		goto out;

	err = nfs_idmap_init();
	if (err)
		goto out1;

	err = nfs4_register_sysctl();
	if (err)
		goto out2;

	register_nfs_version(&nfs_v4);
	return 0;
out2:
	nfs_idmap_quit();
out1:
	nfs_dns_resolver_destroy();
out:
	return err;
}

static void __exit exit_nfs_v4(void)
{
	unregister_nfs_version(&nfs_v4);
	nfs4_unregister_sysctl();
	nfs_idmap_quit();
	nfs_dns_resolver_destroy();
}

MODULE_LICENSE("GPL");

module_init(init_nfs_v4);
module_exit(exit_nfs_v4);
Commit	Line	Data
129d1977 BS	1	/*
	2	* Copyright (c) 2012 Bryan Schumaker <[email protected]>
	3	*/
	4	#include <linux/init.h>
fbdefd64	5	#include <linux/module.h>
129d1977	6	#include <linux/nfs_idmap.h>
fbdefd64	7	#include <linux/nfs4_mount.h>
466bfe7f	8	#include <linux/nfs_fs.h>
19d87ca3	9	#include "delegation.h"
fbdefd64	10	#include "internal.h"
466bfe7f	11	#include "nfs4_fs.h"
c8d74d9b	12	#include "dns_resolve.h"
19d87ca3	13	#include "pnfs.h"
ab7017a3	14	#include "nfs.h"
129d1977	15
fbdefd64 BS	16	#define NFSDBG_FACILITY NFSDBG_VFS
fbdefd64 BS	17
19d87ca3 BS	18	static int nfs4_write_inode(struct inode inode, struct writeback_control wbc);
19d87ca3 BS	19	static void nfs4_evict_inode(struct inode *inode);
fbdefd64 BS	20	static struct dentry nfs4_remote_mount(struct file_system_type fs_type,
fbdefd64 BS	21	int flags, const char dev_name, void raw_data);
fbdefd64 BS	22	static struct dentry nfs4_referral_mount(struct file_system_type fs_type,
	23	int flags, const char dev_name, void raw_data);
	24	static struct dentry nfs4_remote_referral_mount(struct file_system_type fs_type,
	25	int flags, const char dev_name, void raw_data);
	26
fbdefd64 BS	27	static struct file_system_type nfs4_remote_fs_type = {
	28	.owner = THIS_MODULE,
	29	.name = "nfs4",
	30	.mount = nfs4_remote_mount,
	31	.kill_sb = nfs_kill_super,
ecf3d1f1	32	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_BINARY_MOUNTDATA,
fbdefd64 BS	33	};
fbdefd64 BS	34
fbdefd64 BS	35	static struct file_system_type nfs4_remote_referral_fs_type = {
	36	.owner = THIS_MODULE,
	37	.name = "nfs4",
	38	.mount = nfs4_remote_referral_mount,
	39	.kill_sb = nfs_kill_super,
ecf3d1f1	40	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_BINARY_MOUNTDATA,
fbdefd64 BS	41	};
	42
	43	struct file_system_type nfs4_referral_fs_type = {
	44	.owner = THIS_MODULE,
	45	.name = "nfs4",
	46	.mount = nfs4_referral_mount,
	47	.kill_sb = nfs_kill_super,
ecf3d1f1	48	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_BINARY_MOUNTDATA,
fbdefd64 BS	49	};
	50
	51	static const struct super_operations nfs4_sops = {
	52	.alloc_inode = nfs_alloc_inode,
	53	.destroy_inode = nfs_destroy_inode,
	54	.write_inode = nfs4_write_inode,
eed99357	55	.drop_inode = nfs_drop_inode,
fbdefd64 BS	56	.put_super = nfs_put_super,
	57	.statfs = nfs_statfs,
	58	.evict_inode = nfs4_evict_inode,
	59	.umount_begin = nfs_umount_begin,
	60	.show_options = nfs_show_options,
	61	.show_devname = nfs_show_devname,
	62	.show_path = nfs_show_path,
	63	.show_stats = nfs_show_stats,
	64	.remount_fs = nfs_remount,
	65	};
	66
ab7017a3 BS	67	struct nfs_subversion nfs_v4 = {
	68	.owner = THIS_MODULE,
	69	.nfs_fs = &nfs4_fs_type,
	70	.rpc_vers = &nfs_version4,
	71	.rpc_ops = &nfs_v4_clientops,
6a74490d BS	72	.sops = &nfs4_sops,
6a74490d BS	73	.xattr = nfs4_xattr_handlers,
ab7017a3 BS	74	};
ab7017a3 BS	75
19d87ca3 BS	76	static int nfs4_write_inode(struct inode inode, struct writeback_control wbc)
	77	{
	78	int ret = nfs_write_inode(inode, wbc);
	79
	80	if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
	81	int status;
	82	bool sync = true;
	83
	84	if (wbc->sync_mode == WB_SYNC_NONE)
	85	sync = false;
	86
	87	status = pnfs_layoutcommit_inode(inode, sync);
	88	if (status < 0)
	89	return status;
	90	}
	91	return ret;
	92	}
	93
	94	/*
	95	* Clean out any remaining NFSv4 state that might be left over due
	96	* to open() calls that passed nfs_atomic_lookup, but failed to call
	97	* nfs_open().
	98	*/
	99	static void nfs4_evict_inode(struct inode *inode)
	100	{
	101	truncate_inode_pages(&inode->i_data, 0);
	102	clear_inode(inode);
	103	pnfs_return_layout(inode);
	104	pnfs_destroy_layout(NFS_I(inode));
	105	/* If we are holding a delegation, return it! */
	106	nfs_inode_return_delegation_noreclaim(inode);
	107	/* First call standard NFS clear_inode() code */
	108	nfs_clear_inode(inode);
	109	}
	110
fbdefd64 BS	111	/*
	112	* Get the superblock for the NFS4 root partition
	113	*/
	114	static struct dentry *
	115	nfs4_remote_mount(struct file_system_type *fs_type, int flags,
	116	const char dev_name, void info)
	117	{
	118	struct nfs_mount_info *mount_info = info;
	119	struct nfs_server *server;
	120	struct dentry *mntroot = ERR_PTR(-ENOMEM);
	121
fbdefd64 BS	122	mount_info->set_security = nfs_set_sb_security;
	123
	124	/* Get a volume representation */
1179acc6	125	server = nfs4_create_server(mount_info, &nfs_v4);
fbdefd64 BS	126	if (IS_ERR(server)) {
	127	mntroot = ERR_CAST(server);
	128	goto out;
	129	}
	130
ab7017a3	131	mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);
fbdefd64 BS	132
	133	out:
	134	return mntroot;
	135	}
	136
	137	static struct vfsmount nfs_do_root_mount(struct file_system_type fs_type,
	138	int flags, void data, const char hostname)
	139	{
	140	struct vfsmount *root_mnt;
	141	char *root_devname;
	142	size_t len;
	143
	144	len = strlen(hostname) + 5;
	145	root_devname = kmalloc(len, GFP_KERNEL);
	146	if (root_devname == NULL)
	147	return ERR_PTR(-ENOMEM);
	148	/* Does hostname needs to be enclosed in brackets? */
	149	if (strchr(hostname, ':'))
	150	snprintf(root_devname, len, "[%s]:/", hostname);
	151	else
	152	snprintf(root_devname, len, "%s:/", hostname);
	153	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
	154	kfree(root_devname);
	155	return root_mnt;
	156	}
	157
	158	struct nfs_referral_count {
	159	struct list_head list;
	160	const struct task_struct *task;
	161	unsigned int referral_count;
	162	};
	163
	164	static LIST_HEAD(nfs_referral_count_list);
	165	static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
	166
	167	static struct nfs_referral_count *nfs_find_referral_count(void)
	168	{
	169	struct nfs_referral_count *p;
	170
	171	list_for_each_entry(p, &nfs_referral_count_list, list) {
	172	if (p->task == current)
	173	return p;
	174	}
	175	return NULL;
	176	}
	177
	178	#define NFS_MAX_NESTED_REFERRALS 2
	179
	180	static int nfs_referral_loop_protect(void)
	181	{
	182	struct nfs_referral_count p, new;
	183	int ret = -ENOMEM;
	184
	185	new = kmalloc(sizeof(*new), GFP_KERNEL);
	186	if (!new)
	187	goto out;
	188	new->task = current;
	189	new->referral_count = 1;
	190
	191	ret = 0;
	192	spin_lock(&nfs_referral_count_list_lock);
	193	p = nfs_find_referral_count();
	194	if (p != NULL) {
	195	if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
196	ret = -ELOOP;
197	else
198	p->referral_count++;
199	} else {
200	list_add(&new->list, &nfs_referral_count_list);
201	new = NULL;
202	}
203	spin_unlock(&nfs_referral_count_list_lock);
204	kfree(new);
205	out:
206	return ret;
207	}
208
209	static void nfs_referral_loop_unprotect(void)
210	{
211	struct nfs_referral_count *p;
212
213	spin_lock(&nfs_referral_count_list_lock);
214	p = nfs_find_referral_count();
215	p->referral_count--;
216	if (p->referral_count == 0)
217	list_del(&p->list);
218	else
219	p = NULL;
220	spin_unlock(&nfs_referral_count_list_lock);
221	kfree(p);
222	}
223
224	static struct dentry nfs_follow_remote_path(struct vfsmount root_mnt,
225	const char *export_path)
226	{
227	struct dentry *dentry;
228	int err;
229
230	if (IS_ERR(root_mnt))
231	return ERR_CAST(root_mnt);
232
233	err = nfs_referral_loop_protect();
234	if (err) {
235	mntput(root_mnt);
236	return ERR_PTR(err);
237	}
238
239	dentry = mount_subtree(root_mnt, export_path);
240	nfs_referral_loop_unprotect();
241
242	return dentry;
243	}
244
245	struct dentry nfs4_try_mount(int flags, const char dev_name,
ff9099f2 BS	246	struct nfs_mount_info *mount_info,
ff9099f2 BS	247	struct nfs_subversion *nfs_mod)
fbdefd64 BS	248	{
	249	char *export_path;
	250	struct vfsmount *root_mnt;
	251	struct dentry *res;
	252	struct nfs_parsed_mount_data *data = mount_info->parsed;
	253
	254	dfprintk(MOUNT, "--> nfs4_try_mount()\n");
	255
fbdefd64 BS	256	export_path = data->nfs_server.export_path;
	257	data->nfs_server.export_path = "/";
	258	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
	259	data->nfs_server.hostname);
	260	data->nfs_server.export_path = export_path;
	261
	262	res = nfs_follow_remote_path(root_mnt, export_path);
	263
6706246b GB	264	dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n",
	265	PTR_ERR_OR_ZERO(res),
	266	IS_ERR(res) ? " [error]" : "");
fbdefd64 BS	267	return res;
	268	}
	269
fbdefd64 BS	270	static struct dentry *
	271	nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
	272	const char dev_name, void raw_data)
	273	{
	274	struct nfs_mount_info mount_info = {
6a74490d	275	.fill_super = nfs_fill_super,
fbdefd64 BS	276	.set_security = nfs_clone_sb_security,
	277	.cloned = raw_data,
	278	};
	279	struct nfs_server *server;
	280	struct dentry *mntroot = ERR_PTR(-ENOMEM);
	281
	282	dprintk("--> nfs4_referral_get_sb()\n");
	283
	284	mount_info.mntfh = nfs_alloc_fhandle();
	285	if (mount_info.cloned == NULL \|\| mount_info.mntfh == NULL)
	286	goto out;
	287
	288	/* create a new volume representation */
	289	server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
	290	if (IS_ERR(server)) {
	291	mntroot = ERR_CAST(server);
	292	goto out;
	293	}
	294
ab7017a3	295	mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
fbdefd64 BS	296	out:
	297	nfs_free_fhandle(mount_info.mntfh);
	298	return mntroot;
	299	}
	300
	301	/*
	302	* Create an NFS4 server record on referral traversal
	303	*/
	304	static struct dentry nfs4_referral_mount(struct file_system_type fs_type,
	305	int flags, const char dev_name, void raw_data)
	306	{
	307	struct nfs_clone_mount *data = raw_data;
	308	char *export_path;
	309	struct vfsmount *root_mnt;
	310	struct dentry *res;
	311
	312	dprintk("--> nfs4_referral_mount()\n");
	313
	314	export_path = data->mnt_path;
	315	data->mnt_path = "/";
	316
	317	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
	318	flags, data, data->hostname);
	319	data->mnt_path = export_path;
	320
	321	res = nfs_follow_remote_path(root_mnt, export_path);
6706246b GB	322	dprintk("<-- nfs4_referral_mount() = %d%s\n",
	323	PTR_ERR_OR_ZERO(res),
	324	IS_ERR(res) ? " [error]" : "");
fbdefd64 BS	325	return res;
	326	}
	327
	328
89d77c8f	329	static int __init init_nfs_v4(void)
129d1977 BS	330	{
	331	int err;
	332
c8d74d9b	333	err = nfs_dns_resolver_init();
129d1977 BS	334	if (err)
	335	goto out;
	336
c8d74d9b	337	err = nfs_idmap_init();
466bfe7f BS	338	if (err)
	339	goto out1;
	340
c8d74d9b TM	341	err = nfs4_register_sysctl();
	342	if (err)
	343	goto out2;
	344
ab7017a3	345	register_nfs_version(&nfs_v4);
129d1977	346	return 0;
c8d74d9b	347	out2:
466bfe7f	348	nfs_idmap_quit();
c8d74d9b TM	349	out1:
c8d74d9b TM	350	nfs_dns_resolver_destroy();
129d1977 BS	351	out:
	352	return err;
	353	}
	354
89d77c8f	355	static void __exit exit_nfs_v4(void)
129d1977	356	{
ab7017a3	357	unregister_nfs_version(&nfs_v4);
466bfe7f	358	nfs4_unregister_sysctl();
129d1977	359	nfs_idmap_quit();
c8d74d9b	360	nfs_dns_resolver_destroy();
129d1977	361	}
89d77c8f BS	362
	363	MODULE_LICENSE("GPL");
	364
	365	module_init(init_nfs_v4);
	366	module_exit(exit_nfs_v4);